CAMBRIAN VENTURES · FINTECH · PRE-SEED & SEED
Fintech is 1% done.
First checks for the founders building the other 99%. Cambrian backs pre-seed and seed fintech — non-lead, fast, and plugged into the deepest operator network in the category.
Ex-a16zSolo GP since 2022San Francisco
Proof · Fund I graduation
Half of my first fund reached Series A.
The industry average is 15.4%. Small fund, high conviction, one decision-maker — it adds up to a graduation rate more than triple the benchmark.
Fund I: 33 companies. ~50% raised a Series A vs. Carta's 15.4% benchmark for the cohort.
Thesis
Money connects everything.
I don't invest in themes. I back founders with a unique market vision and the raw ability to execute against it — then help them plug into the network.
Share of global financial-services revenue captured by fintech.
Money connects everything.
So the mandate is all of fintech — payments, payroll, banking infrastructure, wealth, insurance — not one narrow theme. Where money moves, there's something to build.
Fintech is 1% done.
Roughly 1% of global financial-services revenue has moved to fintech. The other 99% is the opportunity — and it's why the earliest checks matter most.
AI-native from day one.
Founders now ship multi-product companies immediately. Every — banking, accounting, tax, treasury, payroll in one — is the archetype for what comes next.
How I invest
First check.
Then the whole network.
I write small, early, non-lead checks — on purpose. Deliberately small means I'm here to help, not to own the round. You get a fast yes and a direct line into the deepest bench of fintech operators anywhere.
- Stage
- Pre-seed & seed
- Check size
- $100K – $500K
- Core check
- ~$500K, non-lead
- Position
- Collaborative — never competing with your lead
- Decision
- Rex, alone. Fast and personal.
- Geography
- US-first — SF & NYC. Open to exceptional anywhere.
- Focus
- Fintech only
- What to send
- A short note on what you're building
Portfolio · Featured
Founders I've written first checks to.
33 companies · Fund I & II
A slice of the 33. Marquee anchor: Deel, backed while Rex was at a16z — the archetype is a founder building a multi-product company from day one.
Explore the full portfolio ↗Operators, founders & friends across fintech
The moat · Content & community
The edge is distribution, not capital.
A weekly podcast, a 20,000-strong newsletter, and a founder-only Slack — the community predates the fund and underwrites it. When you take a first check, you plug into all of it.
Recent guests on Cambrian Fintech
Fintech, decoded weekly.
What's actually happening at the earliest stage — read by 20,000 founders, operators and investors.
The network
The network does the work.
Small fund, deep bench. Founders get co-investment, distribution and hiring help from the operators who actually built fintech — not a logo wall of introductions that never happen.
Backed by people who built the category.
Operators from NerdWallet, Plaid, Betterment, Melio and SoFi — with institutional LPs (a bank and a life-insurance company) added in Fund II. They co-invest and open doors.
Where fintech founders start.
A founder-only room that started as grassroots SF meetups. It came before the fund — and it's still the best reason to be here.
About · Rex Salisbury
I've been the engineer and the a16z partner.
A banker who quit, learned to code, helped build a16z's fintech practice, and now writes first checks alone. The site is built for the kind of founder I back — so it was made by one who codes.
- —Investment bankerHated it. Quit, moved across the country.
- 2015Fintech software engineerLearned to build at a mortgage startup.
- a16zFounding member, fintech practiceHelped start Andreessen Horowitz's fintech team. Invested in Deel.
- 2022Cambrian Ventures — solo GPLeft to write the first checks myself. Fund I, then Fund II.
Based in San Francisco — office in Jackson Square, home in the Presidio. Wife and three kids. Foils at Crissy Field during naptime. If that sounds like a person and not a firm, good: it's one person deciding, fast.
FAQ · For founders
Questions, answered plainly.
01Who is Rex Salisbury?
Rex Salisbury is the founder and solo GP of Cambrian Ventures. He was a founding member of Andreessen Horowitz's fintech practice, and before that a fintech software engineer and an investment banker. He writes first checks to pre-seed and seed fintech founders from San Francisco.
02What does Cambrian invest in?
Fintech, broadly — Cambrian backs strong founding teams building at the earliest stages, from payments and payroll to banking infrastructure, wealth and AI-native financial software. Rex bets on founders and market vision, not themes.
03What stage and check size?
Pre-seed and seed. Checks run roughly $100K–$500K, with a core check around $500K, typically non-lead — Cambrian collaborates with lead firms rather than competing with them.
04How do I pitch Cambrian?
Submit your deck through the form at cambrian.vc or email rex@cambrian.vc with what you're building. Rex decides alone, so it's fast and personal. US-first (SF Bay Area and NYC), open to exceptional founders anywhere.
First check. Whole network.
Send me your deck.
First, non-lead checks at pre-seed and seed. One person decides, and it's quick. If you're building in fintech, tell me what you're making.
or just email rex@cambrian.vc